ABSTRACT
Transform techniques such as the Fourier and Laplace transforms and the z-transform have long been used in a wide variety of scientific and engineering disciplines [1,2]. In a number of applications in which we require a joint time-frequency picture, it is necessary to consider other types of transforms or timefrequency representations. Many such methods have evolved. The wavelet transform (WT) technique [3-5] in particular has some unique advantages over other kinds of time-frequency representations such as the short-time Fourier transform (STFT). For historical developments as well as many technical details and original material, see Ref. [5]. This chapter describes some of these representations and explains the advantages of the wavelet transform, as well as the reason for its recent popularity.
